Deaths of 14 cloned animals a setback for gene experts

Matilda, the country's first cloned sheep, has died unexpectedly just short of her third birthday.

Mayzi, Australia's second cloned cow, died last year, aged two, as did 12 genetically modified cloned cows. However, Holly, the first GM cow, is still alive, as is Mayzi's older and more famous cloned sister, Suzi.

Ian Lewis, of the Co-operative Research Centre for Innovative Dairy Products, said yesterday that Mayzi's death did not appear to be related to her cloned birth.

The holstein developed a severe udder infection, called acute toxic mastitis, soon after the birth of her calf, Mayhem, last July. No underlying abnormalities were found that might have predisposed her to the condition.");document.write("

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The deaths of the 12 GM cows, however, were the result of problems with the technology. Dr Lewis said the cells from which the cows were cloned appeared to be at fault rather than the genetic modification technique. "It is distressing. But this research is still in its early days," he said.

The GM cows are different from Suzi and Mayzi because of an extra gene that produces more protein in their milk.

Simon Walker, of the South Australian Research Development Institute, where Matilda was created, said the institute had been re-evaluating its methods during the past year after finding that for every healthy cloned lamb born about five had abnormalities. "We decided we needed to catch our breath and cast a critical eye over what was going on," he said.

The most common problem was breathing difficulties at birth. Matilda's death, however, was unexpected. She was fed last Saturday afternoon and then found dead on Sunday morning.

"It was a shock. She has been so healthy. She was our mascot and she'd been hand-reared by everyone so she had a special place in the lab," Dr Walker said.

He said an independent autopsy had failed to identify a cause of death. The merino had been monitored daily since her birth in April 2000. Normal sheep live from seven to 10 years. "So it's a blank spot in the life and times of Matilda."